1. Field of the Invention:
The present invention relates in general to the completion of oil and gas wellbores and in particular to perforation and fracturing operations which are performed during completion operations.
2. Description of the Prior Art:
Those skilled in the art of welibore completions, and particularly fracturing operations, have realized a significant incidence of premature and unexpected screenout of wellbore fractures which cannot be accounted for adequately by various explanations set forth in the prior art literature. When these screenouts are relatively near the wellbore they frustrate further completion operations. These screenouts frustrate the essential goal of fracturing operations which is to enhance production of hydrocarbons from the wellbore by creating relatively wide and long fractures which allow reservoir fluids to drain from the formation into the wellbore for production. These near-wellbore screenouts can have serious negative economic impact on a particular wellbore, and may result in the eventual shutting in of a wellbore which would have been otherwise considered to be a profitable well. A variety of explanations for these near-welibore screenouts are set forth in the literature. None of the explanations accurately explain the occurrence of this phenomena, and certainly none of these publications suggest an industry accepted or adopted prophylactic or remedial operation which can be performed to prevent or reverse the undesirable near-wellbore screenouts.